CVE-2026-66005
MEDIUMJan Local API Server CORS Origin Reflection via 0.0.0.0 Binding
Title source: cnaDescription
Jan through 0.8.4, fixed in commit 3e1c1e7, contains a CORS misconfiguration vulnerability in its local API server that allows network-adjacent attackers to bypass trusted host restrictions by exploiting the server's replacement of user-configured trusted hosts with a wildcard that reflects arbitrary origins with credentials. Attackers on the local network or using DNS rebinding can reach the unauthenticated OpenAI-compatible API to perform inference, enumerate models, invoke MCP tools, and read cross-origin responses.
References (4)
Core 4
Core References
Patch patch
Patch Commit
https://github.com/janhq/jan/commit/3e1c1e724f696620d89bb4a9cc18a380e0753757
Third Party Advisory third-party-advisory
https://www.vulncheck.com/advisories/jan-local-api-server-cors-origin-reflection-via-binding
Exploit technical-description
exploit
issue-tracking
Researcher Disclosure
https://github.com/janhq/jan/issues/8453
Scores
CVSS v3
6.3
EPSS
0.0019
EPSS Percentile
8.6%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
partial
Details
CWE
CWE-183
CWE-942
Status
published
Products (2)
janhq/jan
< 0.8.4
janhq/jan
3e1c1e724f696620d89bb4a9cc18a380e0753757
Published
Jul 24, 2026
Tracked Since
Jul 24, 2026